Opc ua client subscription does not trigger notification

[vegard77]

In my c# opc ua server application (based on reference server implementation) I have a List containing all items/variables to be published in each publish cycle. An eventhandler call this onpublish method using a Timer and all items in the list is published.

Normally everything seems to work fine, and the client recieves the notifications on items being published. But then I realized the client sometimes doesnt recieve a notification.

This happens when the List containing items to be published, contains the same item/variable twice or more. For a client subscribing, the value of a monitored item will then change rapidly. It looks like the client does not recieve a notification on such rapid changes on the server side.

Any suggestions on what could cause this behavior? The client use mode reporting.
The queue size is set to 0, on the monitored items. Is the minimumsamplinginterval on server side relevant when mode is reporting? 5000 ms on the monitoreditems?

I need some help to understand!

I have temporarily solved this by making sure the List of variables/items to be published does not contain any identical items. And if so moved those items from the List to a delayed List - to be published on the next publishing cycle. Then there is enough time between the published item values, and the client recieves the correct chain of notifications.

Anyway I think this is a hack and it should not be necessary?

-Vegard-